Exhibit 99.1

                     VALERO MERGER QUESTIONS - STOCK OPTIONS

Q 1. What happens to my stock options when Valero merges with UDS?

         At  the   Closing   Date  of  the   merger,   it  will  be   deemed   a
         Change-in-Control  ("CIC") for the purposes of UDS stock  options.  The
         following changes to your options will result:

          |X|  All UDS  options  outstanding  on the date of the CIC will become
               fully vested and exercisable as options to purchase Valero common
               stock.

          |X|  The number of Valero  Stock  Options will equal the number of UDS
               Stock  Options  multiplied  by the Exchange  Ratio rounded to the
               nearest whole share.1

          |X|  The Valero Stock  Option will have a price per share  (rounded to
               the  nearest  one-hundredth  of a cent)  equal  to the per  share
               exercise  price of the UDS Stock  Option  divided by the Exchange
               Ratio.

              The Exchange Ratio =
              [$27.50 + (0.614 x Valero Average Closing Price2)]
              divided by
              Valero Average Closing Price2

              Illustration:

              Assume the Valero Average  Closing Price is $55, and that you have
              100 UDS  Stock  Options  outstanding  with an  Exercise  Price  of
              $30.125 per option:

              [$27.50 + (0.614 x $55)] divided by $55 = Exchange Ratio

              [$27.50 + $33.77] divided by $55 = Exchange Ratio

              [$61.27] divided by $55 = 1.114 Exchange Ratio




Options

      UDS Options              Multiply by Exchange         Fractional Valero         Rounded Valero Options
                                      Ratio                      Options
- ------------------------     -------------------------    ----------------------     -------------------------

                                                                                   
          100                         1.114                       111.4                        111




Exercise Price

  UDS Exercise Price         Divide by Exchange Ratio     Valero Exercise Price      Rounded Valero Exercise
                                                                                              Price
- ------------------------     -------------------------    ----------------------     -------------------------

                                                                                  
        $30.125                       1.114                     $27.0422                      $27.04



Q 2.     What impact does retirement have on my stock options?

         If you retire3 before the CIC:

          |X|  stock  options  originally  issued by Ultramar  Diamond  Shamrock
               continue  to be  exercisable  for the  shorter  of 5 years  after
               retirement or the remaining time to the option's expiration date;
               stock options that are not vested at the time of  retirement  are
               forfeited;
          |X|  stock options  originally  issued by Diamond Shamrock continue to
               be exercisable for the shorter of 2 years after retirement or the
               remaining time to the option's expiration date;
          |X|  stock  options  originally  issued  by  Ultramar  continue  to be
               exercisable  for the shorter of 5 years after  retirement  or the
               remaining time to the option's expiration date
          |X|  stock  options   originally   issued  by  Total  continue  to  be
               exercisable  for the shorter of 2 years after  retirement  or the
               remaining time to the option's expiration date.

         If you retire3 after the CIC:

          |X|  stock  options  originally  issued by Ultramar  Diamond  Shamrock
               continue  to be  exercisable  for the  shorter  of 5 years  after
               retirement or the remaining time to the option's expiration date;
          |X|  stock options  originally  issued by Diamond Shamrock continue to
               be exercisable for the shorter of 2 years after retirement or the
               remaining time to the option's expiration date;
          |X|  stock  options  originally  issued  by  Ultramar  continue  to be
               exercisable  for the shorter of 5 years after  retirement  or the
               remaining time to the option's expiration date;
          |X|  stock  options   originally   issued  by  Total  continue  to  be
               exercisable  for the shorter of 2 years after  retirement  or the
               remaining time to the option's expiration date.

Q 3.     How do I exercise my stock options before the CIC? After the CIC?

         To  exercise  your  options  before the CIC,  you must  continue to use
         Merrill  Lynch.  If you have not  previously  set up your  account with
         Merrill Lynch,  please contact Ken Drayden  (210-592-4455),  Carol Puga
         (210-592-4034), or David Rico (210-592-4896). Information on exercising
         stock options after the CIC will be provided at a later date.

Q 4.     How do I know if I have any stock options outstanding?

         We will be sending a report to all employees with  outstanding  options
         in the near  future.  If you have any  questions,  please  contact  Ken
         Drayden  (210-592-4455),  Carol  Puga  (210-592-4034),  or  David  Rico
         (210-592-4896).  After  the  CIC,  you will be  provided  with a report
         regarding  the  conversion  of your UDS stock  options to Valero  stock
         options (see Q 1 above).

Q 5.     How do I know if my stock options were originally  issued by Ultramar,
         Diamond Shamrock, Total, or Ultramar Diamond Shamrock?

         We will include a legend on the report that will be sent to you (see Q
         4).


- --------
1 Since former Total  Petroleum  employees  hold incentive  stock  options,  the
conversion  of your  options  may differ in order to  preserve  incentive  stock
option treatment.

2 The Valero  Average  Closing  Price  means the  average of the daily last sale
prices of Valero  Common  Stock as reported on the NYSE (as reported in the Wall
Street Journal) for the ten  consecutive  full trading days in which such shares
are traded on the NYSE ending at the close of trading on the third  business day
prior to the Closing Date.

3 Retire  means an  employee's  (a) early  retirement  (retirement  from  active
employment  with the  Company  or a  Subsidiary  in  accordance  with the  early
retirement  provisions  of a pension  plan  maintained  by the  Company  or such
Subsidiary) or (b) normal retirement (retirement from active employment with the
Company or a Subsidiary in accordance with the normal retirement provisions of a
pension plan maintained by the Company or such Subsidiary).